The present application is subdivided into 16 sections, i.e.: Sections X.Y, where X=1,2,3 or 4 and Y=1,2,3 or 4.
The sections where X=1 are sections relating to the preamble to the description; the sections where X=2 are sections relating to listing of the figures; the sections where X=3 are sections relating to the description of the figures; and the sections where X=4 are sections relating to the claims.
The sections where Y=1, i.e. Sections 1.1, 2.1, 3.1 and 4.1 and associated FIGS. 1-14 have been taken as a whole from NL-A 1 012 150 with date of filing May 25, 1999. Section 1.1 is the preamble to the description of NL-A 1 012 150, Section 2.1 is the list of figures in NL-A 1 012 150; Section 3.1 is the description of the figures in NL-A 1 012 150 and Section 1.4 contains the claims of NL-A 1 012 150. It should be clear that Sections 1.1, 2.1, 3.1, 4.1 and the associated FIGS. 1-14 can in the future be split off in isolation from the present application as an individual application without any problem. It is not precluded that these sections will be supplemented from other sections when they are split off, as will be clear from the remainder of the application.
The sections where Y=2, i.e. Sections 1.2, 2.2, 3.2 and 4.2 and associated FIGS. 15-25 have been taken as a whole from NL-A 1 013 933 with date of filing Dec. 23, 1999. However, the figure numbers and reference numerals have been adjusted to prevent duplication with FIGS. 1-14 from NL-A 1 012 150. It should once again be clear that Sections 1.2, 2.2, 3.2, 4.2 and the associated FIGS. 15-25 can in the future be split off from the present application as an individual, isolated application, without any problem. It should also be clear from the remainder of this application that material from other sections of this application could be added hereto.
Sections 1.3, 2.3, 3.3, 4.3 and the associated FIGS. 25-32 relate to a particular embodiment disclosed in NL 1 012 150 (that as such is identical to the content of Sections 1.1, 2.1, 3.1, 4.1 and associated FIGS. 1-14) and further developments thereof. It should once again be clear that Sections 1.3, 2.3, 3.3 and 4.3 and the associated FIGS. 26-32 can in the future be split off from the present application as an individual, isolated application without any problem and that this could also be done in combination with the material from Sections 1.1, 2.1, 3.1, 4.1 and associated FIGS. 1-14. It should also be clear from the remainder of this application that material from other sections of this application could be added hereto.
Sections 1.4, 2.4, 3.4 and 4.4 relate to a number of inventions, such as, inter alia, more detailed embodiments or particular embodiments of the subjects of Sections 1.1 , 2.1, 3.1, 4.1 and 1.2, 2.2, 3.2 and 4.2. Various aspects from Sections 1.4, 2.4, 3.4 and 4.4 and associated figures, on their own or in combination with material from other sections and figures, could also lead to split-off applications in the future.
Where reference is made below to Section X.1, this is intended to be a reference to Sections 1.1, 2.1, 3.1 and 4.1 and the associated figures. Where reference is made below to Section X.2, this is intended to be a reference to Sections 1.2, 2.2, 3.2, 4.2 and the associated figures. Where reference is made below to Section X.3, this is intended to be a reference to Sections 1.3, 2.3, 3.3, 4.3 and the associated figures. Where reference is made below to Section X.4, this is intended to be a reference to Sections 1.4, 2.4, 3.4, 4.4 and the associated figures.
Where the term xe2x80x9cfirst, second, third embodiment and/or first, second, third, etc. aspectxe2x80x9d or xe2x80x9cinventionxe2x80x9d is used in a Section X.1, X.2, X.3 or X.4 in the present application, this must be read as relating to the relevant Section X.1, X.2, X.3 or X.4. It is thus possible, for example, for mention to be made of a first embodiment in Section 3.3 and for this to be a different embodiment from a first embodiment mentioned in Section 3.4.
In all sections of this application a portal fixing device is understood to be a device which is fixed to a vascular wall provided with a passage and is positioned around said passage in order to feed through said passage, for example, a cannula or other surgical or medical instrument or vascular fixing device or implant, such as valve or ring fixing device, or the obturator prosthesis fixing device to be mentioned below. The opening delimited by the tubular element of such a portal fixing device can be (temporarily) fully open, but can also be occluded by a (temporary) membrane, sphincter or valve mechanism. Such a portal fixing device can also serve as a coupling piece for a cannula or a working conduit, which may or may not be provided with said membranes, sphincters or valves. In the case of the last-mentioned applications, the portal fixing device can first be joined to the vascular tissue or element, after which the portal fixing device is joined to the cannula or the working conduit. It is also possible for the portal fixing device already to be integrated with the cannula or working conduit, so that only the join to the tissue has to take place. After removal of the cannula, medical or surgical instrument, implant, working conduit, etc. via or from the portal fixing device, the portal can be closed off by means of a cap. Such a cap can be made of or covered by anticoagulant material, such as carbon, carbon coating, urethane, urethane coating, heparin, heparin-like materials, but also by vascular tissue or pericardium, which may or may not be from the patient him/herself, or vascular prosthesis materials such as, for example, Dacron or Teflon. That side of the cap which can come into contact with the blood can also consist of a network structure, which is optionally coated with absorbable material such as, for example, PDS, to promote the growth of endothelial cells.
In all sections of this application an obturator prosthesis fixing device is understood to be a device for fixing an obturator prosthesis, optionally the entire obturator prosthesis itself, which can be used to close one or more holes or cavities in blood vessels or organs, such as, for example, in the case of an atrium or ventricle septum defect, rupture of the ventricle septum or aorta, true or false aneurysms, fistulas, etc. It is optionally conceivable with this arrangement for the tubular element already to be closed on the inside from the start and, for example, to assume the form of a closed disc. The materials which can be used for this will consist of the same materials or coatings as mentioned above for the cap for closing off the portal fixing device, in any event on the side or sides which can come into contact with blood.
Where STS anastomosis is mentioned in any section of this application, this refers to a so-called side-to-side anastomosis.
Where ETS anastomosis is mentioned in any section of this application, this refers to a so-called end-to-side anastomosis.
Where ETE anastomosis is mentioned in any section of this application, this refers to a so-called end-to-end anastomosis.
Wherever tube-like or tubular is mentioned in any section of this application it will be clear that this can also be understood to mean tube-like or tubular elements which are short in the axial direction, or ring-like or annular elements.
It is pointed out that where reference is made in any section to inner flange, outer flange, bottom flange, top flange, flange segments, etc. said flanges can always be either flanges which extend uninterrupted or flanges which extend with interruptions (which then are thus made up of flange sections with gaps between them).
The present invention relates to a cardiac prosthesis fixing device comprising a tubular element which can be accommodated within a valve annulus of a heart and is provided with a bottom flange and a top flange, the bottom and top flanges extending in the peripheral direction of the tubular element, and the bottom and top flanges having a first position in which they extend outwards from the tubular element in order to be able to accommodate the valve annulus between them.
A cardiac prosthesis fixing device of this type is disclosed in U.S. Pat. No. 3,143,742 and in U.S. Pat. No. 3,574,865.
U.S. Pat. No. 3,143,742 discloses an inner ring 3, provided with external screw thread, and two rigid flanges provided with corresponding internal screw thread. By screwing the flanges over the inner ring the flanges can be turned towards one another in order to clamp the annulus in the vertical direction. Arc-shaped clasps are also provided between the flanges, the points of which clasps are driven outwards as the flanges are turned towards one another, in order to pierce tissue close to the valve annulus for fixing.
U.S. Pat. No. 3,574,865 discloses two flanges which can be joined to one another via a snap-fit joint in order to enclose tissue between them. With this arrangement the snap-fit joint is obtained by pressing an annular section, which widens towards the outside and has been formed as an integral whole with the one flange, into an annular recess, which widens towards the outside, in the other flange. In addition, pins, which extend in the direction from the one flange to the other flange and which, when the flanges are snapped together, pierce the tissue to be accommodated between the flanges, are also provided for fixing.
When fitting a valve prosthesis to replace a natural heart valve, in general the natural so-called valve cusps are cut away, after which the natural valve annulus remains behind at the location of the original valve. The natural valve annulus is a ligament on the inside of the blood vessel which extends in the peripheral direction of the blood vessel and forms a local constriction in the blood vessel. A valve prosthesis is frequently attached to this valve annulus. Notwithstanding what is known from the abovementioned U.S. Pat. No. 3,143,742 and U.S. Pat. No. 3,574,865, general practice is that a so-called suture ring made of textile material consisting of synthetic fibres (usually Dacron or Teflon) is attached to the valve annulus by suturing. A second annular, rotatable housing containing the valve cusps has already been located in this suture ring during production. In this context the valve prosthesis can be entirely synthetic, but can also be an animal or human donor prosthesis. Fixing the suture ring in place, referred to as suturing in, is a time-consuming activity which on average takes 30 to 60 minutes. Throughout this time the heart has been stopped with the aid of a heart/lung machine since the heart and/or the major blood vessels have to be opened for the operation.
Stopping the heart is damaging to the heart, and is so in proportion to the time for which the heart is stopped. Consequently, what it comes down to is that the shorter the period for which the heart is stopped the better this is for the patient. There is thus a need for a fixing technique which takes only little time, at least in any event takes appreciably less time than the current manual suture technique. Furthermore, the fixing technique must be reliable in the sense that the fixing is reliable and essentially leak-tight. Insofar as the devices disclosed in U.S. Pat. No. 3,143,742 and U.S. Pat. No. 3,574,865 meet this requirement, the positioning of, in particular, the bottom flange, that is to say the flange facing the heart, is, however, difficult since this flange has to pass through a local constriction in the form of the valve annulus, which has a diameter smaller than that of the bottom flange. Moreover, currently an increasing number of valve operations are carried out xe2x80x9cminimally invasivexe2x80x9d. In this case there is then little space available for surgical suturing of the suture ring or for complex manipulation of separate components. There is thus a need for mechanisation or robotisation of the implantation.
The aim of the present invention is to provide a heart valve fixing device which makes reliable fixing of the heart valve prosthesis to the natural heart or a blood vessel possible, which fixing moreover can be produced relatively rapidly and preferably demands few manual fixing operations.
These aims are achieved with a cardiac prosthesis fixing device of the type indicated in the preamble in that the bottom flange is bent, or can be bent, reversibly, against a resilient force, from the first position into a second position in which the projection of the bottom flange on a radial transverse surface of the tubular element is located essentially on and/or within the periphery of the tubular element; and in that the bottom flange is fixed or can be fixed in said second position in such a way that the fixing can be released in order to bend back the bottom flange towards the first position under the influence of said resilient force.
In the case of the cardiac prosthesis fixing device according to the invention the terms bottom and top flange are intended primarily to differentiate between a first and a second flange. The terms bottom and top are certainly not intended to differentiate between a flange located in a lower position and a flange located in a higher position relative to one another in the vertical direction. The bottom flange is in particular understood to be the flange which, when feeding the cardiac prosthesis fixing device towards the fixing location, is located on that side of the valve annulus which faces the heart and has to pass through said valve annulus when positioning the cardiac prosthesis fixing device in order to be able to accommodate the valve annulus between the two flanges. If the direction in which the cardiac prosthesis fixing device is fed towards the valve annulus were to be vertical, the so-called bottom flange is then actually the flange located at the top and the so-called top flange is actually the flange located at the bottom.
When fitting the cardiac prosthesis fixing device, in particular when bringing it into its position, the bottom flange will already have been fixed to the tubular element or integrated therewith and have been brought into its second position, also referred to as the extended position, and fixed in place. Taking into account that the diameter of the tubular element is sized such that this fits between the valve annulus, this means that the bottom flange is able to pass through the valve annulus when in its second position. After the bottom flange has been inserted through the valve annulus, the fixing of the bottom flange can be released or removed, after which the bottom flange is able to return to the first position, or at least towards the first position, under the influence of the resilient force. Thus, the bottom flange is then able, in the first position, as it were to hook behind the valve annulus and, together with the top flange, which optionally can be fitted afterwards, to enclose the valve annulus. With this arrangement the valve annulus is enclosed between the bottom and top flanges and then acts as a reliable fixing point for fixing the cardiac prosthesis fixing device and valve prosthesis provided therein or valve prosthesis which may still have to be fitted therein. Because the valve annulus locally constricts the passage in which the valve prosthesis has to be fitted, the cardiac prosthesis fixing device according to the invention can be moved relatively easily through the relatively wider passage since the tubular element and the bottom flange in its second position have a diameter which is able to pass through the valve annulus and thus have a diameter which makes feeding through the passage, in particular a blood vessel, in the direction of the valve annulus possible. With this arrangement the tubular element and the bottom flange in the second position can optionally have an external diameter such that the whole can be fed through the passage to the annulus with some play. So as to be able to allow the tubular element to abut tightly on the valve annulus, which, inter alia, promotes sealing, the tubular element will have a diameter such that, or at least will be chosen by the surgeon with a diameter such that, it can be accommodated in the valve annulus with some stretching of the latter.
According to a further particular embodiment of the invention, it is advantageous if the top flange is bent, or can be bent, reversibly from the first position, against a resilient force, into a second position in which the projection of the top flange on a radial transverse surface of the tubular element is located essentially on and/or within the periphery of the tubular element; and if the top flange is fixed, or can be fixed, in said second position in a manner such that the fixing can be released in order to cause the top flange to bend back in the direction of the first position under the influence of said resilient force. In this way it is possible for the top flange already to be fixed to the tubular element, and optionally integrated therewith, before fitting the cardiac prosthesis fixing device and, at the same time, to ensure an adequate play in the passage via which the cardiac prosthesis fixing device has to be fed to its destination, the valve annulus, or at least to ensure easy feeding to said valve annulus. After all, the top flange also can then have a diameter narrower than the diameter of the passage via which the whole has to be fed.
Both in the case of the bottom flange and in the case of the top flange, if the latter has at least been bent, or is bendable, into a second position, the releasable fixing in the second position can be produced in a number of ways. Consideration can be given, inter alia, to making the cardiac prosthesis fixing device of a so-called memory metal, such as, for example, a nickel-titanium alloy. With such a construction the bottom and top flanges can be brought from the first position into the second position in order then, as it were, to freeze in said second position. This fixing can then be cancelled by heating the cardiac prosthesis fixing device, or at least the respective memory metal part thereof, above a certain temperature, after which the bottom, and optionally the top, flange return to their first position under the influence of the pretensioning. With this construction the so-called second position is, as it were, a frozen position which is cancelled by exceeding a certain temperature or at least releasing the frozen pretensioning forces. With this construction the temperature above which the fixed second position is released can be adjusted by means of suitable choice of the composition of the memory metal alloy. Releasable fixing in the second position can also be achieved in other ways. This will be further discussed further below.
In order to achieve clamping of the valve annulus it is advantageous according to the invention if, in the first position, the axial spacing between the bottom and the top flange, in particular the outside edges thereof, is less than the thickness of the valve annulus to be accommodated between them in order to be able to clamp the valve annulus between the bottom and top flanges in the assembled position. Specifically, on returning from the second position to the first position the bottom and top flanges will come into contact with the valve annulus before achieving the so-called first position at a point in time when there is still residual pretensioning force present in order to bend back the bottom and, respectively, top flange further in the direction of the so-called first position.
Clamping of the valve annulus can, moreover, also be ensured or, supplementary thereto, also further ensured if the bottom and the top flange in the first position are in a position in which they are pretensioned facing towards one another. This can be achieved, for example, by making the cardiac prosthesis fixing device available to the medical specialist with a spacer clamped between the bottom and top flanges. Before fitting the heart valve fixing device the bottom and, if appropriate, also the top flange must then be brought into and fixed into its/their second position, the spacer then being removed.
The bottom and top flanges can each be a flange extending uninterrupted around the periphery of the tubular element. However, it is also very readily conceivable to construct both the bottom flange and the top flange or one of these two flanges as an interrupted flange. In this context the flange constructed as an interrupted flange can, as it were, consist of flange lips or flange fingers which are separated from one another in the circumferential direction by cut-outs or incisions. Assuming an essentially round tubular body and cut-outs, the angular spacing between adjacent flange lips or fingers can then be, for example, 5, 10 or more degrees. The cut-outs or incisions can also extend over a much smaller angular spacing of 1 degree or even less, in which case the incisions are more or less pure incised slits. In order to facilitate, in particular, bringing the bottom and/or top flange from a first into a second position and causing the bottom and/or top flange to return from said second position to the first position, it is particularly advantageous according to the invention if the bottom and/or top flange comprises a number of fingers arranged distributed around the periphery of the tubular element and separated from one another by incisions, cut-outs or folds. Furthermore, it can also be advantageous if the inner flange and optionally also the outer flange have a more or less uninterrupted and an interrupted section. For example, the central section of the flange can be uninterrupted (which improves the seal with the annulus) and the peripheral section can be constructed as an interrupted section with fingers (which promotes firm fixing to the tissue).
In order, in particular, to restrict the number of further manual or at least medical operations, and thus the duration of the operation, after fitting the cardiac prosthesis fixing device, it is advantageous according to the invention if the tubular element is integrated with a valve or ring prosthesis or with a, preferably round or cylindrical, housing thereof. In this context integrated must be understood to mean that the valve or ring prosthesis or housing thereof has already been fixed to the tubular element prior to fitting or, in the extreme case, has been formed as an integral whole therewith. In practice, fixing of the valve prosthesis to the tubular element will preferably take place in such a way that the valve prosthesis is still turnable relative to the tubular element (about a longitudinal axis of the tubular element) in order to be able accurately to position the valve prosthesis.
With a view to accessibility of the tubular element during implantation, in particular the fixing to the surrounding tissue, it can be advantageous according to the invention if the tubular element and the valve prosthesis are assembled together only after implantation of the cardiac prosthesis fixing device. With a view to this it is advantageous according to the invention if the tubular element is provided with a lower limit in order to prevent a valve prosthesis positioned in the tubular element after implantation of the cardiac prosthesis fixing device from becoming detached in the downward direction from the tubular element and/or with a top closure in order to prevent a valve prosthesis fitted in the tubular element after implantation of the cardiac prosthesis fixing device from becoming detached in the upward direction from the tubular element. With this arrangement the lower limit and top closure do not necessarily have to be provided at the bottom and the top, respectively, of the tubular element. The point at issue here is that the lower limit prevents the valve prosthesis from being able to detach from the tubular element in the downward direction and that the top closure prevents the valve prosthesis from being able to detach from the tubular element in the upward direction. According to one embodiment, the lower limit can comprise a stop, such as an inward-pointing rib extending in the peripheral direction, arranged inside the tubular element at the bottom thereof. According to the invention the top closure can comprise a screw ring or snap-fit ring and/or resilient lips. It is also conceivable that the lower limit and top closure are provided simultaneously by the same elements. In this context consideration can be given, inter alia, to internal screw thread in the tubular element which is able to interact with external screw thread on the valve prosthesis or a bayonet fitting or a bayonet-like closure.
In order to improve the clamping of the valve annulus, it is advantageous according to the invention if the bottom and top flanges are at least partially arranged in accordance with a sinusoidal pattern in the peripheral direction of the tubular element. The reason for this is that the valve annulus, in particular in the case of an aortic valve, follows a sinusoidal pattern and that in this way the bottom and top flanges can be matched to the path of this sinusoidal pattern. The shape of the valve annulus will in general be dependent on the type of heart valve, such as aortic valve, mitral valve, pulmonary valve or tricuspid valve. Practice has shown that in other respects more or less standardised dimensions, in particular as far as the so-called diameter is concerned, can be maintained for the various types of heart valves. What this comes down to is that the heart valves are made available in various standardised sizes and that, before or during the surgical operation, the correct size for the patient is determined and the correct standardised heart valve or cardiac prosthesis fixing device is taken.
As far as the shape and size of natural heart valves are concerned, it can be pointed out in a general sense that natural heart valves consist of two or three valve cusps which are attached to the heart or a major blood vessel along a rim or a ligament. This rim or ligament, the valve annulus, can be calcified to a greater or lesser extent, which is usually the case if a valve prosthesis has to be fitted. The mitral valve consists of two valve cusps and the annulus in the case of a mitral valve is located in a more or less flat plane. The aortic valve consists of three valve cusps, the attachment of the valve cusps being half-moon-shaped, as a consequence of which the natural annulus of the aortic valve has a half-moon shape with three troughs at the location of the middle of the valve cusps and three peaks at the location of the commissura. The shape of the opening is more or less circular in the case of the three-cusp aortic valve and is somewhat kidney- or bean-shaped in the case of the two-cusp mitral valve. In principle, the cardiac prosthesis fixing device according to the invention can be used with any type of heart valve. According to the invention, this means that the so-called tubular element according to the invention does not have to have a circular shape, certainly in the case of a so-called mitral ring prosthesis. The shape of a cardiac prosthesis fixing device for a mitral ring prosthesis according to the invention could, in essence, also be kidney-shaped or bean-shaped as well as circular.
In particular if the cardiac prosthesis fixing device is intended for fixing an aortic valve prosthesis, the sinusoidal path of the bottom and top flanges will have a length of three sine periods together spanning the circumference of the tubular body. In particular in the case of a cardiac prosthesis fixing device for an aortic valve prosthesis, it is furthermore also very readily conceivable that the tubular element is a sinusoidally wave-shaped ring or sinusoidally wave-shaped cylindrical element with three sine periods.
If the valve annulus to be accommodated between the bottom and top flanges has a sinusoidal shape three periods long, as is the case with the annulus of the aortic valve, it is advantageous according to the invention if:
the top and bottom flanges comprise flange segment for clamping the sine wave troughs of the valve annulus, which flange segments are preferably positioned approximately 120xc2x0 apart; and/or
the top and bottom flanges comprise flange segments for clamping the sine wave peaks of the valve annulus, which flange segments are preferably positioned approximately 120xc2x0 apart; and/or
the top and bottom flanges comprise flange segments for clamping the sine wave origins of the valve annulus, which flange segments are preferably positioned approximately 60xc2x0 apart.
The advantage of this is that in the case of such a sinusoidally wave-shaped valve annulus said valve annulus can be gripped by means of a segmented, in general discontinuous, bottom flange and optionally discontinuous top flange. With this arrangement the point of fixation to the valve annulus, that is to say the sine wave peaks and/or sine wave troughs and/or sine wave origins, can be chosen depending on the anatomy and/or condition of the valve annulus of the patient concerned. From the standpoint of accessibility, it will frequently be preferable to opt for clamping the sine wave peaks, which are, in fact, on the side facing away from the heart, which in general is the easiest to reach. However, depending on the anatomy and/or condition of the valve annulus, other locations for clamping the valve annulus can be chosen, depending on the patient. The fact that the fixing of the cardiac prosthesis fixing device becomes more reliable and robust with more clamping points should be obvious. A leak-tight seal on the valve annulus can be further ensured by making the segments sufficiently broad and/or making the top flange continuous and optionally rigid (that is to say not bendable into a second position) and/or using supplementary additional segments and/or constructing the tubular body such that it is an oversized fit in the valve annulus (which is then stretched somewhat) and/or some other means.
In order to improve the closure along the outer surface of the tubular element and to be able reliably to ensure this, it is advantageous according to the invention if the outer surface of the tubular element is concave. In this context it is optionally even possible for this concavity to continue into the bottom and/or top flange, which bottom and/or top flange then, as it were, form the ends of the concavity.
In order further to improve the anchoring or fixing of the cardiac prosthesis fixing device according to the invention it is advantageous according to the invention if the bottom and/or top flange or fingers of the bottom and/or top flanges is/are provided with anchoring means, such as barbs, points or roughenings, for anchoring in the valve annulus. Said barbs, points or roughenings, referred to in general as anchoring means, can then penetrate into the tissue of the valve annulus and fasten therein. For the same purpose it is also possible for roughenings to be provided on the outside of the tubular element.
Although, according to the invention, use can be made of memory metals, such as nickel-titanium alloys, which are fixable/freezable in a pretensioned state, it is preferable according to the invention if the cardiac prosthesis fixing device further comprises fixing means for releasably fixing the bottom and/or top flange in the second position. Such fixing means can comprise at least one annular element, such as a sleeve, ring or suture, which are placed or can be placed around the bottom and/or top flange, when the flange is in the second position, in order to fix the bottom and, respectively, top flange in their second position. When the cardiac prosthesis fixing device has then been brought into place inside the valve annulus, the fixing means can be removed or the fixing effect thereof can be cancelled. According to a particularly preferred embodiment, the fixing means comprise a sleeve in which the tubular element with the bottom flange in the second position and optionally the top flange in the second position can be accommodated or have been accommodated in such a way that the tubular element, the bottom flange and the optional top flange can be pushed out of the sleeve by retracting the sleeve from the tubular element in the longitudinal direction facing away from the bottom flange. In this way the entire heart valve fixing device, which may or may not already be provided with the heart valve prosthesis, accommodated in a sleeve can be brought into position inside the valve annulus, after which the sleeve can be withdrawn and the bottom and, optionally, top flange can return to a first position so that the bottom and top flanges together are able to engage/enclose the valve annulus. However, according to the invention it is also very readily conceivable for the fixing means to comprise a suture, such as a ligature, which is stretched taut around the bottom flange in the second position and for the two ends of the suture to run over the outside of the tubular element to that side of the tubular element which faces away from the bottom flange in order to be fixed in place at that side or beyond that end, it being possible to remove the suture after detaching the one end of the suture by pulling on the other end of the suture and those parts of the suture running over the tubular element preferably being guided in guide means. Such an embodiment with which the fixing means for fixing the bottom flange comprise a suture is in particular advantageous when the cardiac prosthesis fixing device has already been provided with the valve prosthesis concerned prior to fitting. Specifically, in such a case it is less sensible to remove, or at least to cut through or cut, the suture around the bottom flange between the valve cusps. This is because the valve cusps could easily be damaged while doing this. With this arrangement the guide means through which the suture sections preferably run have the advantage that cutting of the suture into the valve annulus tissue is counteracted when pulling away the suture. The guide means themselves can also be constructed such that they are also removable and then are withdrawn after removing the suture. Fixing means, such as a suture or ligature, can also be highly advantageously used with the top flange. Since the latter is still accessible from above after fitting, without going through the tubular element, guide means are superfluous and the suture will not have to run over the tubular element either on the inside or on the outside. If the valve prosthesis itself, that is to say the replacement for the valve cusps, is placed in the tubular body only after fitting and fixing the tubular body, the ends of the suture for fixing the bottom flange in the second position can then also run through the tubular body on the inside to the accessible top thereof since it is also possible via the passage through the tubular element to reach the bottom thereof in order to remove the suture.
The cardiac prosthesis fixing device according to the invention can be used both with completely synthetic heart valve prostheses and with biological heart valve prostheses, which can originate from animal or human donors and which may or may not have stents. The cardiac prosthesis fixing device according to the invention can also be used with so-called ring prostheses, which are used to xe2x80x9crepairxe2x80x9d the diameter of the opening of a leaking valve (usually the mitral valve) by constricting this by means of a ring only. This ring can be placed inside and constrict the diameter of the opening by being engaged by the annulus. Such ring prostheses can be uninterrupted or interrupted and can be round or bean/kidney-shaped.
As far as the flanges are concerned, the cardiac prosthesis fixing device will in particular have been made of a relatively stiff material. The flanges can themselves be bendable against a resilient force or can optionally be mounted on supports, such as arm-like bodies, which are bendable against a resilient force. The cardiac prosthesis fixing device according to the invention can, in particular, have been produced from a metal suitable for implantation. In practice for such applications metals are frequently coated with a carbon coating to counteract clotting. The cardiac prosthesis fixing device, and in particular also the flanges thereof, can be coated on the outside with textile-like material in order to make tissue ingrowth possible and for leak-tight covering of the gap between the tubular element and the valve annulus. Materials of this type are usually made of Dacron or Teflon-like synthetic fibres. This textile-like material can also have been treated with substances which counteract blood clotting and/or infections.
In accordance with the invention, the cardiac prosthesis fixing device according to the invention can also very readily be used for fixing vascular prostheses in major vessels. In this respect the term cardiac prosthesis fixing device must therefore be considered to be broader than a fixing device for fixing prostheses in passages or conduits through which blood flows.
The present invention relates to a prosthesis fixing device, such as for a cardiac prosthesis, comprising a tubular element intended to lie, when the cardiac prosthesis fixing device is in the fitted position, with the outside in contact with the peripheral wall of part of the circulatory system and to accommodate a valve prosthesis inside it, the tubular element having pins arranged distributed around the periphery, which pins penetrate the peripheral wall when the device is in the fitted position.
A cardiac prosthesis fixing device of this type is disclosed in U.S. Pat. No. 3,143,742. This device comprises two flange-like rings which are mounted on a common sleeve provided with screw thread and can be moved towards one another over said screw thread by screwing in order to clamp annulus tissue or possibly some other type of circulatory system wall tissue between them. Both flange-like rings are provided with passages through which anchoring pins can be pressed outwards. With this arrangement the pins are shaped as an arc of a circle and pressure is exerted on the pins which run through passages in the one flange-like ring by the other flange-like ring on moving the two flange-like ring elements towards one another, so as to emerge at the outside in order to penetrate circulatory system wall tissue. This known cardiac prosthesis fixing device has a number of disadvantages. One significant disadvantage is that the fitting of this known cardiac prosthesis fixing device, in particular the clamping of the annulus tissue and simultaneous penetration of the circulatory system wall tissue by the pins, is much less simple than it appears. Firstly, the flange-like rings make it more difficult to position the cardiac prosthesis fixing device in place since these rings must have an external diameter greater than that of the annulus to be clamped and therefore it is relatively difficult for them to pass through the annulus to be clamped. In order to move the flange-like elements towards one another the inner sleeve, provided with external screw thread, has to be turned whilst the ring-like flanges have to be prevented from turning with the sleeve. Turning the inner sleeve, provided with external screw thread, for this purpose will, inter alia, require some force and partly for this reason is difficult to operate remotely by means of catheter-like aids. Furthermore, there is a risk that some turning of the inner sleeve relative to the ring-like flanges can already occur when manoeuvring the sleeve into its destination, as a consequence of which the points of the pins can emerge outwards prematurely. These points can then damage the wall tissue of the circulatory system. Furthermore, it must be pointed out that according to FIG. 10 of U.S. Pat. No. 3,143,742, the points of the upper pins already protrude beyond the upper flange-like ring in advance and thus will already be able to give rise to tissue damage on manoeuvring the ring into its position. Furthermore, the cardiac prosthesis fixing device according to U.S. Pat. No. 3,143,742 consists of a relatively large number of separate components, which is not only a disadvantage from the cost point of view but, moreover, also makes production more difficult and, perhaps even more importantly, increases the risk of failure. If just one of the pins cannot be pushed properly outwards, this is sufficient to impede further screwing of the ring-like flanges towards one another and thus to make the reliability of the fixing of the cardiac prosthesis fixing device uncertain.
The aim of the present invention is to provide an improved cardiac prosthesis fixing device of the type indicated in the preamble. In particular, the aim of the invention is to provide a cardiac prosthesis fixing device which is very reliable, in particular with regard to the fixing on fitting.
The abovementioned aim is achieved according to the invention in that each pin is arranged on an arm which is attached by one end to the tubular element in a manner which permits swinging about a hinge axis, such as via a fold line or bending line, and in that the arms and pins are movable, by swinging about the hinge axis, from an insertion position, in which they are essentially located inside the tubular element, into a fixing position in which at least the pins, viewed in the radial direction, project outside the tubular element. Because the pins are completely inside the tubular element, that is to say inside an imaginary infinitely continual circumferential surface thereof, during insertion, it can be ensured that, on feeding the cardiac prosthesis fixing device to its destination, the pins are not able prematurely to come into contact with the surrounding tissue material of the circulatory system and thus are not able to impede manoeuvring of the device to its destination and possibly to cause damage. Furthermore, the cardiac prosthesis fixing device according to the invention can be produced as an integral whole, although, if desired, it can also be made up of a number of components. A further advantage is that swinging the arms, with the pins thereon, outwards in order to penetrate surrounding tissue of the circulatory system can be achieved in a manner which is not only very simple but also very reliable, inspection afterwards also being readily possible. For example, use can be made of a balloon to be inflated within the circumferential plane defined by the arms or of another type of element that is capable of exerting forces directed radially outwards. Visual inspection from the inside can take place afterwards using known means, by checking whether all arms, and thus also the pins formed thereon or fixed thereto, have swung sufficiently far outwards.
In order to be able to ensure with a high degree of certainty that the pins, or at least the points at the ends thereof, are not able to come into contact with surrounding tissue of the circulatory system while manoeuvring the pins into their destination, it is preferable according to the invention if the pins are located within the longitudinal boundaries of the tubular element in the insertion position and if the tubular element is provided with radial passages located alongside the pins in the radial direction, in particular slit-shaped passages extending in the longitudinal direction of the arms, such that the pins emerge through these passages on swinging from the insertion position into the fixing position. Thus, the tubular element will completely shield the pins from surrounding tissue of the circulatory system while manoeuvring into its destination.
In order to simplify the outward swinging of the arms, with the pins provided thereon, it is preferable if the arms, viewed in the longitudinal direction of the tubular element, extend essentially in said longitudinal direction. This makes it possible, certainly if all arms are oriented in the same direction with respect to the longitudinal axis, to swing said arms outwards by pressing a ring or forcing body, having a diameter greater than the diameter determined by those parts of the arms and/or pins located radially furthest to the inside and a diameter smaller than the internal diameter of the tubular element, between the arms in the longitudinal direction into the tubular element. Such a forcing body could be, for example, the valve prosthesis, or at least a surrounding ring thereof. Furthermore, it is pointed out that it is certainly not necessarily the case that this forcing body has to be pressed between the arms by means of a compressive force, but that it is very readily possible for said forcing body to be driven into the tubular element from one side by pulling a pull element, joined to the forcing body, from the other side. In this context it is particularly preferable if the arms, viewed from the hinge axis, point away from the heart in the insertion position.
According to a further advantageous embodiment, each arm can have at least two, in particular two, pins. In this way the robustness of the fixing can be improved and, moreover, it is possible to penetrate the valve annulus from opposing sides.
In order to improve not only the fixing of the cardiac prosthesis fixing device, but in particular also the seal thereof with the surrounding tissue of the circulatory system wall, it is preferable according to the invention if the tubular element has a bottom and/or top flange extending in the circumferential direction of the tubular element, which flange, at least in the fitted position, projects outwards with respect to the tubular element in order to come into contact with, or at least to overlap, the bottom or, respectively, the top of the valve annulus. In order, in particular, to make it possible with this arrangement for the bottom or, respectively, top flange to point outwards with respect to the tubular element after positioning of the cardiac prosthesis fixing device at its destination, it is preferable according to the invention if the bottom or, respectively, top flange has a number of flange fingers separated from one another by incisions, cut-outs or folds and arranged distributed around the periphery of the tubular element. In this way it is possible to maintain the bottom or, respectively, top flange in the position in which it is extended with respect to the tubular element, or optionally in the inward-pointing position, while manoeuvring into its destination and to bend the bottom or, respectively, top flange into a position in which it points radially outwards only when it is at its destination. In order to ensure that the valve prosthesis to be fitted after positioning the cardiac prosthesis fixing device is not able to detach from the cardiac prosthesis fixing device, it is preferable according to the invention if the tubular element is provided with a lower limit in order to prevent a valve prosthesis placed in the tubular element after implantation of the cardiac prosthesis fixing device from detaching from the tubular element in the downward direction, and/or with a top closure in order to prevent a valve prosthesis placed in the tubular element after implantation of the cardiac prosthesis fixing device from detaching from the tubular element in the upward direction. With this arrangement, the lower limit can be a stop arranged inside the tubular element at the bottom thereof, such as an inward-pointing rib extending in the circumferential direction. With this arrangement the top closure can be a screw ring-or a snap-fit ring and/or resilient snap-fit lips.
In order always to be able to orient the valve prosthesis in a specific desired position with respect to the circulatory system, irrespective of the precise rotational position of the cardiac prosthesis fixing device, it is preferable according to the invention if the valve prosthesis can be accommodated in the tubular element such that it can be turned about its longitudinal axis, for example by means of a screw thread connection, a bayonet connection or a combination of a peripheral recess in the one part and one or more ribs on the other part interacting therewith, the cardiac prosthesis fixing device preferably also being provided with a twist lock in order to be able to fix the tubular body and the valve prosthesis in a desired position with respect to one another.
In order to be able to ensure that the pins penetrate the valve annulus as much as possible, in the case of a sine wave-shaped valve annulus, as is the case with the annulus of the aortic valve, it is preferable according to the invention if the arms and fingers are arranged at least partially in accordance with a sine wave-like pattern in the peripheral direction of the tubular element. In this context, it is particularly preferable if the sine wave path has a length of three sine periods together spanning the periphery of the tubular body. Furthermore, according to the invention it can be advantageous in this context if the tubular element is a sine-wave-shaped ring or sine-wave-shaped cylindrical element with three sine wave periods.
In order to facilitate the outward swinging of the arms provided with pins so that surrounding wall tissue is penetrated by the pins, and in particular to restrict or at least to reduce as far as possible the exertion of forces on the cardiac prosthesis fixing device during this operation, it is preferable according to the invention if the arms provided with pins have been bent, or can be bent, against a resilient force from an initial position, corresponding to essentially the fitted position, into the insertion position and are fixed or can be fixed in said insertion position in such a way that the fixing can be released in order to cause the arms provided with pins to bend back to, or at least in the direction of, the fitted position under the influence of the resilient force.
In order to improve the abutment of the cardiac prosthesis fixing device with a valve annulus and, in particular, the seal with said valve annulus, it is preferable according to the invention if at least part of the external surface of the tubular element is concave.
With regard to the material in claims 28-38 of this application, considered separately from the other claims, reference can be made for embodiments and further explanation to Netherlands Patent Application 1 012 150 which was filed on May 25, 1999, has not previously been published and is incorporated as an integral part of this PCT application by means of Sections 1.1, 2.1, 3.1, 4.1 and associated FIGS. 1-14.
The present invention relates to a fixing device for fixing to vascular wall tissue, comprising a tubular element which can be accommodated within a passage surrounded by vascular wall tissue and is provided with bottom fingers arranged distributed in the peripheral direction of the tubular element and with top fingers arranged distributed in the peripheral direction of the tubular element, the bottom and top fingers having a first position in which they project outwards from the tubular element with respect to the axial direction of the tubular element in order to be able to accommodate between them the vascular wall tissue surrounding the passage.
A fixing device of this type in the form of a cardiac prosthesis fixing device is disclosed in U.S. Pat. No. 3,143,742 and in U.S. Pat. No. 3,574,865. These publications have both already been discussed at the start of Section 1.1 and therefore it now suffices to refer to the description given there, which can be considered as being incorporated here.
When fitting a fixing device, such as, in accordance with the present invention, in particular a vascular prosthesis fixing device, a portal prosthesis fixing device or an obturator prosthesis fixing device, in a passage surrounded by vascular wall tissue, the fixing device will have to engage on the vascular wall tissue surrounding the passage and at least part of the device will also have to pass through this passage. Furthermore, the fixing device usually has to be fed via the circulatory system to the passage in which the fixing device has to be fitted. When it has reached its destination, the fixing of the fixing device to the vascular wall tissue surrounding the passage must be reliable, robust for a prolonged period and preferably also quick and effective to produce.
The aim of the present invention is to provide an improved fixing device, for fixing to vascular wall tissue, which meets the above requirements.
According to the invention said aim is achieved in that both the bottom and the top fingers have been bent aside, or can be bent aside, reversibly, against a resilient force, from the first position into a second position in which the projection of the bottom and top fingers on a radial transverse surface of the tubular element is located essentially on and/or within the periphery of the tubular element; and in that the bottom and top fingers are fixed or can be fixed in said second position by a sleeve in which tie tubular element and at least part of the bottom and top fingers which are in the second position have been accommodated or can be accommodated such that the tubular element, the bottom fingers and the top fingers can be slid completely out of the sleeve by sliding the sleeve in the longitudinal direction of the tubular element, in order to allow the bottom and top fingers to return to the first position. In the so-called first position, which essentially corresponds to the position after fixing, the fingers project outwards with respect to the tubular body in order to accommodate between them the vascular wall tissue that surrounds the passage in which the fixing device is to be fitted. The fingers are, as it were, directed, against a resilient force, along the tubular body, or at least along the imaginary tube surface defined by the tubular body (if the tubular body is shorter or appreciably shorter in the axial direction than the longitudinal direction of the fingers) and held in said position, directed along the tubular body or optionally within the tubular body, by placing a sleeve around the whole. The sleeve is then inserted through the passage, in which the fixing device is to be fitted, until it is correctly positioned, after which the sleeve is withdrawn in one direction in order to release first the bottom fingers (or possibly the top fingers) and then the other fingers, the top fingers (or possibly the bottom fingers), and to allow these to return to their original position under the influence of the resilient force, generated on bringing into the extended position, and in doing so to accommodate between them the vascular wall tissue surrounding the passage. This enclosure between them can be clamping, but it is also conceivable that the fingers puncture said vascular wall tissue and anchor in this way or optionally in combination clamp and penetrate the surrounding vascular wall tissue. The sleeve also makes it easier to feed the device to its destination, that is to say the passage in which the fixing device is to be fitted, and, moreover, at the same time ensures that the means with which the fixing device is fixed to the surrounding vascular wall tissue, that is to say the top and bottom fingers and possibly supplementary anchoring means, remain shielded from surrounding tissue and thus are not able to damage this surrounding tissue.
Although it is not essential, it is advantageous according to the invention if the bottom and top fingers extend essentially axially in opposing directions in the second position. What is achieved in this way is that the bottom and top fingers move towards one another in order to accommodate vascular wall tissue between them. However, it is not entirely precluded that the bottom and top fingers extend in the same axial direction from the tubular body or the sleeve arranged around the latter, in which case it is then an advantage if the bottom fingers are shorter than the top fingers or, vice versa, that the top fingers are shorter than the bottom fingers, so that first the one type of fingers and then the second type of fingers go into their first position. A corollary of this embodiment will usually be that the sleeve is first partially slid off, in order then to position the fixing device precisely in place, and only then to slide the sleeve completely off.
According to a further advantageous embodiment, the bottom and top fingers will, in the first position, extend in the radial direction with respect to the tubular body.
According to a further advantageous embodiment, the sleeve is provided with an end which is sloping or tapered or curved with respect to the axial direction thereof. In particular said sloping, tapered or curved end will have been made sharp close to the outermost end of the sleeve. What this amounts to in the case of the sleeve being cut off at a slope is that the sloping cut runs at an angle of less than 45xc2x0 with respect to the axial direction. This has the advantage that the sleeve can be used in order first to cut a passage of suitable size at the location where the fixing device has to be fitted, or to cut the passage somewhat larger if it is not large enough. It should be clear that the end edge of the sleeve will be made sharp for this purpose.
According to a further advantageous embodiment, it is possible, by, in the case of a tapered sleeve, leaving the central part of the tapered end of the sleeve open, to draw the sleeve up over a guide wire. Such embodiments are, for example, useful when producing STS or ETS anastomoses or when fitting prosthesis fixing devices, cannulas or working conduits. The sleeve can then be used for joining end-to-side to a major vessel (this, as it were, produces a T-joint) in order to form a passage in the wall of the major vessel. With this embodiment it can furthermore be advantageous if the ends of the bottom fingers span a surface which is sloping, tapered or curved with respect to the axial direction of the sleeve when the fingers are in the second position. In particular, this surface spanned by the ends of the bottom fingers will then follow the same course as the surface spanned by the sloping, tapered or curved end of the sleeve.
According to a further advantageous embodiment of the invention, the bottom and/or the top fingers can have pointed ends. Such pointed ends can then provide for penetration of the surrounding vascular wall tissue, in which case it is then possible that no clamping of this surrounding vascular wall tissue between the bottom and top fingers has to take place at all. Such clamping is, however, advantageous.
According to a further advantageous embodiment, in their first position, the bottom and/or top fingers define a flange surface extending uninterrupted or with interruptions around the tubular element. The fingers can then be, as it were, flange fingers, as discussed in Section X.1.
The fixing device according to Section X.3 can advantageously be constructed in accordance with various preferred embodiments as described in Section X.1.
In the case of the fixing device according to Section X.3 the terms bottom and top fingers are primarily intended to differentiate between first and second fingers. The terms bottom and top fingers are certainly not intended to differentiate between fingers located at a lower position and fingers located at a higher position with respect to one another in the vertical direction. Bottom fingers are in particular understood to be the fingers which are located closest to the fixing point on feeding to the fixing point, or, in the case of bottom and top fingers pointing in opposing axial directions in the second position, point towards the fixing point, in which latter case the bottom fingers will also pass through the fixing point in order to be able to accommodate the vascular wall tissue around the fixing point between the bottom and top fingers.
According to a first aspect of Sections X.4, the invention relates to a vascular fixing device for fixing the end of a vessel.
Such vascular fixing devices are known, for example for joining two blood vessels end-to-end. In this case use can be made of a fixing device which is attached to the end of the vessel and is then coupled to a fixing device which is joined to the end of another vessel. However, it would also be possible to join the ends of the two vessels to one another at the same time.
According to this first aspect of Sections X.4, the aim of the invention is to provide a vascular fixing device for fixing to an end of a vessel, by means of which the end of the vessel can be fixed rapidly and efficiently to the fixing device.
According to the first aspect of Sections X.4, the abovementioned aim is achieved by providing a vascular fixing device for fixing to an end of a vessel, comprising:
a tubular body having an inner flange formed thereon for accommodating in the interior of the end of the vessel;
an outer flange to be located, in a fixing position, around the end of the vessel, around and in contact with the outside of the vascular wall tissue, which outer flange, in said fixing position, runs around the inner flange and overlaps the latter, the outer flange being bendable or bent from the fixing position, against a resilient force, into a pretensioned fitting position located further away from the inner flange, and the outer flange, in said pretensioned fitting position, being fixable or fixed in such a way that said fixing can be released in order to cause the outer flange to bend back in the direction of the fixing position under the influence of the pretension.
The fixing device can be fixed relatively easily to an end of a vessel by inserting the inner flange in the end of the vessel after the outer flange has first been brought into its pretensioned fitting position. The fixing of the outer flange is then removed and the outer flange is allowed to return to its fixing position under the influence of the pretension in order, in said fixing position, together with the inner flange to clamp the vascular wall tissue located around the end of the vessel. With this arrangement the inner flange can be a rigid inner flange. The inner flange can be, for example, a cylindrical body, in which case the tubular body with inner flange formed thereon can be referred to as a single cylindrical body. The end of the vessel must then be slid over the rigid inner flange, the external diameter of which will then preferably be approximately equal to or smaller than the internal diameter of the end of the vessel.
In order to facilitate the insertion of the inner flange into the end of the vessel, it can, according to an advantageous embodiment of the first aspect of Section X.4, be advantageous if the inner flange is bendable or has been bent from the fixing position, against a resilient force, into a pretensioned fitting position located a greater distance away from the outer flange and if the inner flange is fixable or has been fixed in said pretensioned fitting position in such a way that said fixing can be released in order to cause the inner flange to bend back in the direction of the fixing position under the influence of the pretension. With this arrangement the functioning of the inner flange is essentially the same as that of the outer flange.
According to an advantageous embodiment of the first aspect of Section X.4, the outer flange, and optionally the inner flange, will have been made from a superelastic metal alloy or an alloy with a shape memory which has been activated/can be activated by heat, such as a nickel-titanium alloy, for example nitinol. Using an outer flange, and optionally an inner flange, made from such a material it is possible to bring said flange from the fixing position into a fitting position and to freeze the flange concerned in said fitting position. The frozen position can then be released by heating the flange concerned to above a certain temperature. This temperature can very well be in the region of the body temperature, for example approximately 38xc2x0 to 40xc2x0, or even lower than the body temperature.
According to a further advantageous embodiment of the first aspect of Section X.4, in the fitting position the outer flange extends in a direction essentially opposed to that of the inner flange and the outer flange is fixed or is fixable in said fitting position by means of a sleeve in which the outer flange is accommodated. By subsequently sliding off or otherwise removing the sleeve, the outer flange is then released and is able to snap back, for example through approximately 180xc2x0, into a position running parallel to the inner flange, in which position the outer flange and the inner flange together clamp the end of the vessel.
A fixing device for producing an ETE anastomosis (where two vessels are joined to one another end-to-end) can be implemented advantageously according to the first aspect of Section X.4 if the fixing device comprises two of said inner flanges, which extend essentially in the extension of one another, and two of said outer flanges, which in the fitting position are essentially located transversely with respect to the inner flanges with the outsides facing one another. With such an embodiment the outer flanges can be held in their fitting position by means of a mechanical fixing, for example if the fixing device comprises a U-shaped annular element opening towards the middle, in which the ends of the outer flanges can be accommodated or are accommodated in the fitting position.
According to a further advantageous embodiment, a fixing device can, in accordance with the first aspect of Section X.4, be fixed to another blood vessel if the tubular element is provided all round with suture passages.
According to a second aspect of Sections X.4, the invention relates to a fixing device for fixing in a passage surrounded by vascular wall tissue.
Fixing devices of this type are needed, for example, to produce a so-called ETS anastomosis, for fixing a portal in a vessel wall for a cannula, working conduit or other type of surgical or medical instrument or implant to be inserted via the vessel wall, or as a coupling piece for a cannula or working conduit. Fixing devices of this type in accordance with the invention can also be useful for sealing undesired cavities, passages or connections in a vessel wall or hollow organ, such as, for example, a hole in the atrium or ventricle septum.
The aim of the invention according to this second aspect of Section X.4 is to provide a fixing device for fixing in a passage surrounded by vascular wall tissue, which fixing device can be fitted easily, rapidly and reliably.
To this end the invention in accordance with the second aspect of Section X.4 provides a fixing device for fixing in a passage surrounded by vascular wall tissue, comprising:
a tubular element that delimits a passage,
an outer flange on the tubular element to come into contact, at the access side of the passage, with the vascular wall tissue surrounding the passage,
an inner flange made up of inner flange segments, wherein each inner flange segment is arranged on an arm, one end of which is attached to the tubular element in a manner which allows swinging about a hinge axis, such as via a fold line or bending line, and
wherein the arms and flange segments are movable, by swinging about the hinge axis, from an insertion position, located essentially within the outline of the passage, into a fixing position in which the inner flange segments, overlapping the outer flange, can come into contact, on that side of the passage which faces away from the access side, with the vascular wall tissue surrounding the passage.
The access side is understood to be that side of the vascular wall tissue from which the passage therein is approached. In the case of a blood vessel this can be either the inside or the outside. The fixing device is brought into position by bringing the outer flange of the fixing device, from the access side, into contact with the vascular wall tissue around the passage and then moving the arms with inner flange segments from the insertion position into the fixing position. In the fixing position the vascular wall tissue surrounding the passage will then be clamped between the inner flange segments and the outer flange. With this arrangement it is very readily conceivable that the inner flange segments, or parts thereof, also penetrate the vascular wall tissue. This can be useful, in particular with a view to firm anchoring. With this arrangement the arms with inner flange segments can be brought into their fixing position by exerting a force on the arms, for example by pressing an annular or tubular article between the arms with inner flange segments. Such an annular or tubular article can be, for example, a cannula, an obturator cap to be placed in the fixing device or the end of a vessel which is to be joined to the fixing device and is provided with a further fixing device. The arms with flange segments can, however, also have been bent inwards into their insertion position against a resilient force and automatically return to their fixing position after the fixing is removed. Such a fixing can be a mechanical impediment, such as a suture or ligature stretched around the arms with flange segments. It can also be highly advantageous to make the arms and inner flange segments, or at least the arms, from a superelastic metal alloy or an alloy with shape memory which has been activated or can be activated by heat, such as a nickel-titanium alloy, for example nitinol. As has already been indicated above in connection with the first aspect of Section X.4, the arms with inner flange segments are then able automatically to return to their fixing position from a freezing position after this has been cancelled, for example by heating the arms with inner flange segments to a certain temperature.
In order to prevent a further construction to be connected to a fixing device, which may or may not already have been implanted, being inserted too deeply through the fixing device, it is advantageous in accordance with the second aspect according to Section X.4 if the tubular element is provided with a lower limit in order to prevent a prosthesis, such as an obturator cap or vascular prosthesis or cannula, placed in the tubular element after implantation of the fixing device, from detaching from the tubular element in the downward direction. In order to prevent the further construction detaching from a fixing device in the opposite direction, it is advantageous if the fixing device is provided with a top closure in order to prevent a prosthesis, such as an obturator cap or vascular prosthesis or cannula, placed in the tubular element after implantation of the fixing device, from detaching from the tubular element in the upward direction. Since the second aspect of Section X.4 in particular is a more detailed embodiment of the invention according to Section X.2, the special embodiments outlined in that section also constitute special embodiments of the invention according to the second aspect of Section X.4.